In the recent years, several broadband wireless technologies have been developed to meet growing number of broadband subscribers and to provide more and better applications and services. For example, the Third Generation Partnership Project 2 (3GPP2) developed Code Division Multiple Access 2000 (CDMA 2000), 1× Evolution Data Optimized (1×EVDO) and Ultra Mobile Broadband (UMB) systems. The 3rd Generation Partnership Project (3GPP) developed Wideband Code Division Multiple Access (WCDMA), High Speed Packet Access (HSPA) and Long Term Evolution (LTE) systems. The Institute of Electrical and Electronics Engineers developed Mobile Worldwide Interoperability for Microwave Access (WiMAX) systems. As more and more people become users of mobile communication systems and more and more services are provided over these systems, there is an increasing need for mobile communication system with large capacity, high throughput, lower latency and better reliability.
Super Mobile Broadband (SMB) system based on millimeter waves, i.e., radio waves with wavelength in range of 1 millimeter (mm) to 10 mm, which corresponds to a radio frequency of 30 Gigahertz (GHz) to 300 GHz, is a candidate for next generation mobile communication technology as vast amount of spectrum is available in a millimeter Wave band. In general, an SMB network consists of multiple SMB base stations (BSs) that cover a geographic area. In order to ensure good coverage, SMB base stations need to be deployed with higher density than macro-cellular base stations. In general, SMB base stations are recommended to be deployed roughly the same site-to-site distance as microcell or pico-cell deployment in an urban environment. Typically, transmission and/or reception in an SMB system are based on narrow beams, which suppress the interference from neighboring SMB base stations and extend the range of an SMB link. However due to high path loss, heavy shadowing and rain attenuation reliable transmission at higher frequencies is one of the key issues that need to be overcome in order to make the SMB system a practical reality.
Lower frequencies in a cellular band having robust link characteristics can be utilized with higher frequencies in a millimeter wave (mmWave) band to overcome reliability issues in the SMB systems. In an asymmetric multicarrier communication network, a mobile station (MS) communicates with a base station using asymmetric multiband carriers consisting of at least one low frequency carrier in the cellular band and at least one high frequency carrier in the mmWave band. The primary carrier i.e., carrier operating on low frequencies and the secondary carrier i.e., carrier operating on high frequencies may be transmitted by same BS or different BS. Since the transmission characteristics of low frequency carriers in the cellular band and high frequency carriers in the mmWave band is quite different, transmission time intervals (TTIs) and the frame structures for the primary carrier and secondary carrier may not be same. An example of frame structure for a primary carrier in the cellular band where the operation is based on 3rd Generation Partnership Projects (3GPP) Long Term Evolution (LTE) Standard, and frame structure for a secondary carrier in the mmWave band is illustrated in FIG. 1. In frame structure for the primary carrier in the cellular band, one radio frame of length 10 milliseconds is divided into 10 radio subframes which are further sub-divided into two slots. Each slot is further composed of six or seven Orthogonal Frequency Division Multiplexing (OFDM) symbols. The BS transmits control information in the first three or the first four OFDM symbols of the first slot. The control information is intended for the both the slots of a sub frame. A control channel carrying the control information is referred to as Physical Downlink Control Channel (PDCCH) in 3GPP LTE terminology. In a frame structure for the secondary carrier in mmWave band, a radio frame of 5 milliseconds is composed of 5 subframes of 1 ms each. Each subframe is composed of P=60 slots and each slot is composed of n=4 OFDM symbols.
In an asymmetric multicarrier communication network, a low frequency carrier in a cellular band can be used to signal resource allocation information for high frequency carrier in an mmWave band for reliably signaling the resource allocation information. However, frame structure and transmit time intervals for high frequency carrier is different than those for low frequency carrier.